Online advertisement placements generally refer to the slots or space on the pages of a website that are available for displaying advertisements along with their content. Advertisers typically bid on these advertisement placements that are made available through real-time bidding (RTB) exchanges such as AdX, Admeld, Pubmatic, etc.
From a mechanical perspective, online advertisement placement requires a bidding server connected to RTB exchanges. The bidding server then receives bid requests via the RTB exchanges. A bid request occurs when a user/Internet surfer visits a website or publisher that is selling their advertisement space on an RTB exchange. Upon receiving a bid request, the bidding server has a very short period of time to respond to this request (generally under 50 ms). Since this bid response needs to occur in a very short period of time, it is difficult to run large scale models to predict what advertisements to buy and what price to pay for them.
At bid time, the bidding server has to act on some set of rules, models or system instructions that indicate which bid requests it should bid or pass on. This is a non-trivial problem since there are numerous (e.g., billions) requests that could be bought at any given time, those requests are very different and occur randomly throughout the day, and each request needs to be evaluated in milliseconds.